C# List<> with custom class returns null

I am developing a game in Unity and I came upon a problem.
I am fetching data from file and I wanna store them into List<> with my own class Words.

public class Words
{
    private readonly string _myWord;
    private readonly int _damage;

    public Words()
    {
        _myWord = "";
        _damage = 0;
    }

    public Words(string word, int damage)
    {
        _myWord = word;
        _damage = damage;
    }

    public override string ToString()
    {
        return _myWord + ":" + _damage + "\n";
    }
}

I load the data and store it to the object of my custom class

using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Net;
using UnityEditor;

using UnityEngine;
using UnityEngine.Networking;
using UnityEngine.Serialization;

public class WorkingWithTextFiles : MonoBehaviour
{
    [SerializeField] private TextAsset myFile;
    private List<Words> _wordsList;
    [SerializeField] private string _seperatorParts;
    [SerializeField] private string _seperatorEndOfLine;
    
    // Start is called before the first frame update
    private void Start()
    {
        try
        { 
            var textFromFile = myFile.ToString(); //gets contents of file
            var numberOfWords = int.Parse(textFromFile.Split("\n")[0]) ; //returns number of words - given in file on first line
            textFromFile = textFromFile.Remove(0,3); //deletes number and /n
                
                var word = textFromFile.Split(_seperatorParts)[0]; //gets only the word
                textFromFile = textFromFile.Remove(0, word.Length + 1); //removes the word + separator
                var damage = textFromFile.Split(_seperatorEndOfLine)[0]; //gets only the damage
                textFromFile = textFromFile.Remove(0, damage.Length + 3); //removes the damage + separator + \n
                
                var givenWord = new Words(word, int.Parse(damage));
                
                _wordsList.Add(new Words(word, int.Parse(damage)));
                //Debug.Log(_wordsList.Count);
                Debug.Log(_wordsList.ToString());
                
        }
        catch (Exception e)
        {
           Debug.Log(e);
        }
       
    }

    
}

I take data from file and store it into word and damage. Then I make givenWord from them. They store okay and upon printing they return fine.

Ond the other hand the _wordsList is null.
It’s null when I print out it’s size, it’s null when I print it out using Debug.Log.

>Solution :

Your WorkingWithTextFiles class seemingly never initializes its _wordsList field.

Since a list is a reference type and you never initialize the field, the value it has will always be null. you should initialize it on object creation with private List<Words> _wordsList = new();.
This way, the list you want to add items to actually exists when you call .Add().